Oxytocin response to an experimental psychosocial challenge in adults exposed to traumatic experiences during childhood or adolescence.

Long-term implications of the exposure to traumatizing experiences during childhood or adolescence, such as sexual abuse, or cancer, have been documented, namely the subjects' response to an acute stress in adulthood. Several indicators of the stress response have been considered (e.g. cortisol, heart rate). Oxytocin (OT) response to an acute stress of individuals exposed to trauma has not been documented. Eighty subjects (n=26 women who had experienced episodes of child abuse, n=25 men and women healthy survivors of cancer in childhood or adolescence, and 29 controls) have been submitted to a laboratory session involving an experimental stress challenge, the Trier social stress test. Overall, there was a clear OT response to the psychosocial challenge. Subjects having experienced a childhood/adolescence life-threatening illness had higher mean levels of OT than both abused and control subjects. There was a moderate negative relationship between OT and salivary cortisol. It is suggested that an acute stress stimulates OT secretion, and that the exposure to enduring life-threatening experiences in childhood/adolescence has long-lasting consequences regarding the stress system and connected functions, namely the activation of OT secretion. Better knowledge of such long-term implications is important so that to prevent dysregulations of the stress responses, which have been shown to be associated to the individual's mental health.

Assessment of total energy expenditure in free-living patients with cystic fibrosis.

The increase in resting energy expenditure (REE) reported in patients with cystic fibrosis (CF) does not necessarily imply an increase in total energy expenditure (TEE). In this study REE was assessed with open-circuit indirect calorimetry, and free-living 24-hour TEE with the heart rate method. Thirteen patients with CF, aged 8 to 24 years, with adequate nutritional status and moderately decreased pulmonary function, were studied. They were compared with 13 healthy control subjects matched for gender, age, height, and nutritional status. Resting energy expenditure was higher in patients with CF (1512 +/- 88 kcal/day) than in control subjects (1339 +/- 76 kcal/day; p less than 0.01), whereas free-living 24-hour TEE (2345 +/- 127 kcal/day and 2358 +/- 256 kcal/day, respectively) and net mechanical work efficiency of walking on a treadmill (20.4 +/- 0.7% and 19.8 +/- 0.6%, respectively) were similar. Respiratory quotient was higher in patients with CF than in control subjects at rest (0.834 +/- 0.009 vs 0.797 +/- 0.008; p less than 0.05), and tended to remain so during physical exercise, indicating a higher contribution of carbohydrate oxidation to energy expenditure. We conclude that in free living conditions, patients with CF can compensate for their increase in REE by a reduction in spontaneous physical activities or other yet undefined mechanisms.

Thermogenic effects of commercially available plant preparations aimed at treating human obesity.

Different commercially available plant preparations have been claimed to have anti-obesity action. We investigated the acute effects of oral administration of 12 of these preparations in non-obese women and men. No significant increase in energy expenditure (EE) has been noted after treatment with any of these preparations. No change in respiratory quotient (RQ) was shown, except after treatment with maté (Ilex paraguariensis) extract, where a drop in RQ was observed, indicating a rise in the proportion of fat oxidized. The results suggested the poor potential of these plant preparations in the treatment of obesity, except possibly for the maté extract. Further studies are required to explore the influence of higher dosages of these preparations as well as chronic administration in man.

Obesity markers and blood pressure in a sample of Portuguese children and adolescents.

Little information exists regarding the effect of several obesity markers on blood pressure (BP) levels in youth. Transverse study including 2494 boys and 2589 girls. Height, weight and waist were measured according to the international criteria and body fat (BF) by bioimpedance. BP was measured by an automated device. Hypertension was defined using sex-specific, age-specific and height-specific observation-points. Body mass index (BMI) and waist were positively related with systolic blood pressure (SBP) and diastolic blood pressure (DBP) and heart rate in both sexes, whereas the relationships with BF were less consistent. Stepwise linear regression analysis showed that BMI was positively related with SBP and DBP in both sexes, whereas BF was negatively related with SBP in both sexes and with heart rate in boys only; finally, waist was positively related with SBP in boys and heart rate in girls. Age and heart rate-adjusted values of SBP and DBP increased with BMI: for SBP, 117+/-1, 123+/-1 and 124+/-1 mmHg in normal, overweight and obese boys, respectively; corresponding values for girls were 111+/-1, 114+/-1 and 116+/-2 mmHg (mean+/-SE, P<0.001). Overweight and obese boys had an odds ratio for being hypertensive of 2.26 (95% confidence interval: 1.79-2.86) and 3.36 (2.32-4.87), respectively; corresponding values for girls were 1.58 (confidence interval 1.25-1.99) and 2.31 (1.53-3.50). BMI, not BF or waist, is consistently and independently related to BP levels in children; overweight and obesity considerably increase the risk of hypertension.

Mechanisms of the pressor response to intravenous thyrotropin-releasing hormone in the rat.

1. The purpose of this study was to examine the contribution of the sympatho-adrenomedullary system to the blood pressure response to an intravenous bolus of thyrotropin-releasing hormone (TRH) in conscious medullectomized and sham-operated rats. 2. The peak pressor effect of 0.5 mg TRH was significantly increased in rats having no adrenal medulla (+24.2 +/- 1.6 mmHg, mean +/- s.e.m., P < 0.01) as compared to sham-operated animals (+12.2 +/- 3.0 mmHg). 3. Blockade of alpha-adrenergic receptors with phentolamine abolished the pressor effect of TRH in control rats (+2.1 +/- 1.9 mmHg) but did not attenuate the blood pressure response of medullectomized rats (+21.5 +/- 4.7 mmHg). In contrast, beta-blockade with propranolol blunted the blood pressure responsiveness of rats subjected to adrenal medullectomy (+12.4 +/- 2.6 mmHg) but did not modify the effect of TRH in sham-operated controls (+10.9 +/- 2.9 mmHg). 4. The direct in vitro effect of TRH on isolated mesenteric rat arteries was also evaluated. TRH did not induce contractions of isolated arteries. 5. These results suggest that in rats with intact adrenals, the pressor effect of intravenous TRH is mediated primarily by a stimulation of alpha-adrenergic receptors. Adrenal medullectomy appears to enhance the blood pressure response to intravenous TRH. Activation of cardiac beta-adrenoceptors seems to contribute to the blood pressure increasing effect of intravenous TRH in medullectomized animals.

Oxygen uptake during early cardiogenesis of the chick.

Oxidative metabolism of the isolated embryonic heart of the chick has been determined using a spectrophotometric technique allowing global as well as localized micromeasurements of the O2 uptake. Entire hearts, excised from embryos of 10 somites (primordia fused, stage 10 HH) and 40 somites (S shaped, stage 20 HH) were placed in a special chamber under controlled metabolic conditions where they continued to beat spontaneously and regularly. During the 32 h of development, the O2 consumption of the whole heart increased from 0.9 +/- 0.1 to 5.3 +/- 0.8 nmol O2/h. These values corrected for protein content were, however, comparable (0.45 nmol O2.h-1.micrograms-1). At stage 10-12, the O2 uptake varied along the cardiac tube (from 0.74 to 1.0 nmol O2.h-1.mm-2). From stage 10 to 20, the O2 uptake per unit area of ventricle wall increased from 0.7 +/- 0.2 to 1.8 +/- 0.2 nmol O2.h-1.mm-2, and the O2 uptake per myocardial volume during one cardiac cycle varied from 7 to 2.5 nmol O2/cm3. These results indicate that, despite an intense morphogenesis, the cardiac tissue has a rather low and stable oxidative metabolism, although the O2 requirement of the whole heart increases significantly. Moreover, the normalized suprabasal aerobic energy expenditure decreases throughout early cardiogenesis. The functional integrity of the isolated embryonic heart combined with the experimental possibilities of the microtechnique make the preparation appropriate for studying the changes in cardiac metabolism during development.

Impact of a pain protocol including hypnosis in major burns.

BACKGROUND: Pain is a major issue after burns even when large doses of opioids are prescribed. The study focused on the impact of a pain protocol using hypnosis on pain intensity, anxiety, clinical course, and costs. METHODS: All patients admitted to the ICU, aged >18 years, with an ICU stay >24h, accepting to try hypnosis, and treated according to standardized pain protocol were included. Pain was scaled on the Visual Analog Scale (VAS) (mean of daily multiple recordings), and basal and procedural opioid doses were recorded. Clinical outcome and economical data were retrieved from hospital charts and information system, respectively. Treated patients were matched with controls for sex, age, and the burned surface area. FINDINGS: Forty patients were admitted from 2006 to 2007: 17 met exclusion criteria, leaving 23 patients, who were matched with 23 historical controls. Altogether patients were 36+/-14 years old and burned 27+/-15%BSA. The first hypnosis session was performed after a median of 9 days. The protocol resulted in the early delivery of higher opioid doses/24h (p<0.0001) followed by a later reduction with lower pain scores (p<0.0001), less procedural related anxiety, less procedures under anaesthesia, reduced total grafting requirements (p=0.014), and lower hospital costs per patient. CONCLUSION: A pain protocol including hypnosis reduced pain intensity, improved opioid efficiency, reduced anxiety, improved wound outcome while reducing costs. The protocol guided use of opioids improved patient care without side effects, while hypnosis had significant psychological benefits.

Vibration training elicits a mixed aerobic and resistance-type exercise in sedentary subjects.

Objective. Vibration training (VT) is a new exercise method, with good acceptance among sedentary subjects, due to its passive principle: the machine moves the subject, not the opposite. We hypothesize that untrained subjects can benefit from a greater cardiovascular and metabolic stimulation than trained athletes, resembling classical aerobic-type activity, in addition of eliciting strength gains shown in diverse studies. Methods. 3 group of male subjects, inactive (SED), endurance trained athletes (END) and strength trained athletes (STR) underwent fitness (VO2max) and lower-body strength tests (isokinetic). Subjects were submitted to a session of oscillating VT, composed of 3 exercises (isometric half-squat, dynamic squat, dynamic squat with added load), each of 3 minutes duration, and repeated at 3 frequencies. VO2, heart rate and Borg scale were monitored. Results. 27 healthy subjects (10 SED, 9 END and 8 STR), mean age 24.5 (SED), 25.0 (STR) and 29.8 (END) were included. VO2max was significantly different as expected (47.9 vs. 52.9 vs. 63.9 ml/kg/min, resp. for SED, STR and END). Isokinetic dominant leg extensors strength was higher in STR (3.32 Nm/kg vs. 2.60 and 2.74 in SED and END). During VT, peak oxygen consumption (% of VO2max) attained was 59.3 in SED, 50.8 in STR and 48.0 in END (P<0.001 between SED and other subjects). Peak heart rate (% of heart rate max) was 82.7 in SED, 80.4 in STR and 72.4 in END. In SED, dynamic exercises without extra load elicited 51.0% of VO2max and 72.1% of heart rate max, and perceived effort reached 15.1/20. Conclusions. VT is an unconventional type of exercise, which has been shown to enhance strength, bone density, balance and flexibility. Users are attracted by the relative passivity. In SED, we show that VT elicits sufficient cardiovascular response to benefit overall fitness in addition to the known strength effects. VT's higher acceptance as an exercise in sedentary people, compared to jogging or cycling for example, can lead to better adherence to physical activity. Although long-term effects of VT on health are not avalaible, we believe this type of combination of aerobic and resistance-type exercise can be beneficial on multiple health parameters, especially cardiovascular health.

Elevated energy expenditure and reduced energy intake in obese prepubertal children: paradox of poor dietary reliability in obesity?

The purpose of this study was to assess the validity of two common methods used to assess energy intake. A 3-day weighed dietary record and a dietary history were collected and compared with the total daily energy expenditure (TEE) assessed by the heart rate method in a group of 12 obese and 12 nonobese prepubertal children (mean age 9.3 +/- 1.1 years vs 9.3 +/- 0.4 years). The TEE value was higher in obese than in nonobese children (9.89 +/- 1.08 vs 8.13 +/- 1.39 MJ/day; p < 0.01). Energy intake assessed by the dietary record was significantly lower than TEE in the obese children (7.06 +/- 0.98 MJ/day; p < 0.001) but comparable to TEE in the nonobese children (8.03 +/- 0.99 MJ/day; p = not significant). Energy intake assessed by diet history was lower than TEE in the obese children (8.37 +/- 1.35 MJ/day, p < 0.05) but close to TEE in the nonobese children (8.64 +/- 1.54 MJ/day, p = not significant). These results suggest that obese children underreport food intake and that the dietary record and the diet history are not valid means of assessing energy intake in obese prepubertal children.

The transventricular-transseptal access to the aortic root: a new route for extrapleural trans-catheter aortic stent-valve implantation.

Objective: The aim of this study was to investigate the feasibility of transventricular-transseptal approach (TVSA) for extrapleural transcatheter aortic valved stent implantation via a subxyphoidian access. Methods: In five porcine experiments (52.3 +/- 10.9 kg) the right ventricle was exposed via subxyphoidian access. Under the guidance of intracardiac echocardiography (ICE) and fluoroscopy, the transseptal access from right ventricle to left ventricle was created progressively by puncture and dilation with dilators (8F-26F). Valved stents built in-house from commercial tanned pericardium and self-expandable Nitinol stents were loaded into a cartridge. A delivery sheath was then introduced from the right ventricle into the left ventricle and then into the ascending aorta. The cartridge was connected and the valved stent was deployed in the aortic position. Then, the ventricular septal access was sealed with an Amplatzer septal occluder device and the right ventricular access was closed by tying prepared purse-string suture directly. Thirty minutes after the whole procedure, the animals were sacrificed for macroscopic evaluation of the position of valved stent and septal closure device. Result: Procedural success of TVSA was 100% at the first attempt. Mean procedure time was 49 +/- 4 min. Progressive dilatation of the transseptal access resulted in a measurable ventricular septal defect (VSD) after dilator sizes 18F and more. All valved stents were delivered at the target site over the native aortic valve with good acute valve function and no paravalvular leaks. During the procedure, premature beats (5/5) and supraventriclar tachycardias (5/5) were observed, but no atrial-ventricular block (0/5) occurred. Heart rate before (after) was 90 +/- 3 beats min(-1) (100 +/- 2 beats min(-1): p < 0.05), whereas blood pressure was 60 + 1 mm Hg (55 + 2 mm Hg (p < 0.05)). Total blood loss was 280 + 10 ml. The Amplatzer septal occluder devices were fully deployed and the ventricular septal accesses were sealed successfully, without detectable residual shunt. Conclusion: Trans-catheter implantation of aortic valved stent via extrapleural transventricular-transseptal access is technically feasible and has the potential for a simplified procedure under local anaesthesia. (C) 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B. V. All rights reserved.

Cardiorespiratory responses during running and sport-specific exercises in handball players

To determine whether a 4-a-side handball (HB) game is an appropriate aerobic stimulus to reach and potentially enhance maximal oxygen uptake (V O(2)max), and whether heart rate (HR) is a valid index of V O(2) during a handball game. Nine skilled players (21.0+/-2.9 yr) underwent a graded maximal aerobic test (GT) where V O(2)max and HR-V O(2) relationship were determined. V O(2), HR and blood lactate ([La](b)) were recorded during a 2 x 225 s (interspersed with 30s rest) 4-a-side handball game and were compared to those measured during an 480-s running intermittent exercise (IE). Mean V O(2) tended to be higher in handball compared to IE (93.9+/-8.5 vs. 87.6+/-7.4% O(2)max, p=0.06), whereas HR was similar (92.3+/-4.9 vs. 93.9+/-3.9% of the peak of HR, p=0.10). [La](b) was lower for handball than for IE (8.9+/-3.5 vs. 11.6+/-2.1 mmol l(-1), p=0.04). Time spent over 90% of V O(2)max was higher for handball than for IE (336.1+/-139.6s vs. 216.1+/-124.7s; p=0.03). The HR-V O(2) relationship during GT was high (r(2)=0.96, p<0.001) but estimated V O(2) from HR was lower to that measured (p=0.03) in handball, whereas there was no difference in IE. 4-a-side handball game can be used as a specific alternative to IE for enhancing aerobic fitness in handball players. Nevertheless, the accuracy of HR measures for estimating V O(2) during handball is poor.

Responses to exercise in normobaric hypoxia: comparison of elite and recreational ski mountaineers.

PURPOSE: Hypoxia is known to reduce maximal oxygen uptake (VO(2max)) more in trained than in untrained subjects in several lowland sports. Ski mountaineering is practiced mainly at altitude, so elite ski mountaineers spend significantly longer training duration at altitude than their lower-level counterparts. Since acclimatization in hypobaric hypoxia is effective, the authors hypothesized that elite ski mountaineers would exhibit a VO2max decrement in hypoxia similar to that of recreational ski mountaineers. METHODS: Eleven elite (E, Swiss national team) and 12 recreational (R) ski mountaineers completed an incremental treadmill test to exhaustion in normobaric hypoxia (H, 3000 m, F(1)O(2) 14.6% ± 0.1%) and in normoxia (N, 485 m, F(1)O(2) 20.9% ± 0.0%). Pulse oxygen saturation in blood (SpO(2)), VO(2max), minute ventilation, and heart rate were recorded. RESULTS: At rest, hypoxic ventilatory response was higher (P < .05) in E than in R (1.4 ± 1.9 vs 0.3 ± 0.6 L · min⁻¹ · kg⁻¹). At maximal intensity, SpO(2) was significantly lower (P < .01) in E than in R, both in N (91.1% ± 3.3% vs 94.3% ± 2.3%) and in H (76.4% ± 5.4% vs 82.3% ± 3.5%). In both groups, SpO(2) was lower (P < .01) in H. Between N and H, VO(2max) decreased to a greater extent (P < .05) in E than in R (-18% and -12%, P < .01). In E only, the VO(2max) decrement was significantly correlated with the SpO(2) decrement (r = .74, P < .01) but also with VO(2max) measured in N (r = .64, P < .05). CONCLUSION: Despite a probable better acclimatization to altitude, VO(2max) was more reduced in E than in R ski mountaineers, confirming previous results observed in lowlander E athletes.

Cardiorespiratory responses to the 30-15 intermittent ice test

PURPOSE: In this study, the authors compared the cardiorespiratory responses between the 30-15 Intermittent Ice Test (30-15(IIT)) and the 30-15 Intermittent Fitness Test (30-15(IFT)) in semiprofessional hockey players. METHODS: Ten players (age 24 ± 6 y) from a Swiss League B team performed the 30-15(IIT) and 30-15(IFT) in random order (13 ± 4 d between trials). Cardiorespiratory variables were measured with a portable gas analyzer. Ventilatory threshold (VT), respiratory-compensation point (RCP), and maximal speeds were measured for both tests. Peak blood lactate ([La(peak)]) was measured at 1 min postexercise. RESULTS: Compared with 30-15(IFT), 30-15(IIT) peak heart rate (HR(peak); mean ± SD 185 ± 7 vs 189 ± 10 beats/min, P = .02) and peak oxygen consumption (VO(2peak)); 60 ± 7 vs 62.7 ± 4 mL/min/kg, P = .02) were lower, whereas [La(peak)] was higher (10.9 ± 1 vs 8.6 ± 2 mmol/L, P < .01) for the 30-15(IIT). VT and RCP values during the 30-15(IIT) and 30-15(IFT) were similar for %HR(peak) (76.3% ± 5% vs 75.5% ± 3%, P = .53, and 90.6% ± 3% vs. 89.8% ± 3%, P = .45) and % VO(2peak) (62.3% ± 5% vs 64.2% ± 6%, P = .46, and 85.9% ± 5% vs 84.0% ± 7%, P = .33). VO(2peak ))(r = .93, P < .001), HR(peak) (r = .86, P = .001), and final velocities (r = .69, P = .029) were all largely to almost perfectly correlated. CONCLUSIONS: Despite slightly lower maximal cardiorespiratory responses than in the field-running version of the test, the on-ice 30-15(IIT) is of practical interest since it is a specific maximal test with a higher anaerobic component.

Assessment of free-living physical activity in humans: an overview of currently available and proposed new measures.

The number of physical activity measures and indexes used in the human literature is large and may result in some difficulty for the average investigator to choose the most appropriate measure. Accordingly, this review is intended to provide information on the utility and limitations of the various measures. Its primary focus is the objective assessment of free-living physical activity in humans based on physiological and biomechanical methods. The physical activity measures have been classified into three categories: Measures based on energy expenditure or oxygen uptake, such as activity energy expenditure, activity-related time equivalent, physical activity level, physical activity ratio, metabolic equivalent, and a new index of potential interest, daytime physical activity level. Measures based on heart rate monitoring, such as net heart rate, physical activity ratio heart rate, physical activity level heart rate, activity-related time equivalent, and daytime physical activity level heart rate. Measures based on whole-body accelerometry (counts/U time). Quantification of the velocity and duration of displacement in outdoor conditions by satellites using the Differential Global Positioning System may constitute a surrogate for physical activity, because walking is the primary activity of man in free-living conditions. A general outline of the measures and indexes described above is presented in tabular form, along with their respective definition, usual applications, advantages, and shortcomings. A practical example is given with typical values in obese and non-obese subjects. The various factors to be considered in the selection of physical activity methods include experimental goals, sample size, budget, cultural and social/environmental factors, physical burden for the subject, and statistical factors, such as accuracy and precision. It is concluded that no single current technique is able to quantify all aspects of physical activity under free-living conditions, requiring the use of complementary methods. In the future, physical activity sensors, which are of low-cost, small-sized, and convenient for subjects, investigators, and clinicians, are needed to reliably monitor, during extended periods in free-living situations, small changes in movements and grade as well as duration and intensity of typical physical activities.